"What they have, which I think goes a long way, is they have to really fight to be there [in the US]," said McLoughlin. "Having been in that boat myself, where you have to fight tooth and nail just to stay in the country, you make bloody sure that your business is going to be successful because if you're building a life somewhere the last thing you want is to have to leave and go home."

The British venture capitalist cofounded enterprise collaboration firm Huddle with Alastair Mitchell in London before expanding it to San Francisco and turning it into a company that regularly competes with Box and Dropbox. To date, the company has raised $89.2 million (£59.5 million).

McLoughlin left Huddle to become a full-time investor in December 2014, when the company raised its last round of funding.

He said he'd love to be able to invest in London businesses one day but for now the SoftTech team of five is spread quite thin. "As it is I can come back and meet companies and talk to them about the journey to the US because a lot of companies ultimately do want to end up in San Francisco," he said.